What type of database file is it? The .db extension is not specific to a certain type of database. Though, coming from Android, I presume it's an sqlite database. I don't know of any simple GUIs to browse an sqlite database file, though. Most SQL related tools are far from simple.

From the output of the 'file' command in the comment above I can see that it's an sqlite3 database so all you have to do is open it with the sqlite3 command and export it to CSV. Run the following command:

sqlite3 bookCatalogueDbExport.db

You should see a prompt like this:

sqlite>

If you get an error about "command not found" you'll need to install sqlite3:

sudo apt-get install sqlite3

Verify that sqlite3 can read the database by listing the tables:

sqlite> .tables
books

If you get an error at this point the database is probably encrypted or isn't actually SQLite format (the file command can make mistakes sometimes). If it lists the tables in the .db then you're good to go. Just tell sqlite3 the format you want and have it output all the data:

Now you should have a file named books.csv that you can open directly with LibreOffice Calc.

Note that sqlite databases can have more than one table. If this is the case you'll want to output each table as its own file. So instead of typing '.exit' above you can continue the process like so:

sqlite> .output some_other_table.csv -- Give it a different name
sqlite> select * from some_other_table; -- Replace 'books' with the actual table name
sqlite> .exit -- When done exporting all the tables

Finally, to be as thorough as possible, here's a link to the sqlite syntax in case you want to play around with it some more:

This is an old thread, but I came across it today in Google while looking for a solution and found that the full version of Adminer is another alternative that you can use in a web browser to view SQLite DB files: http://www.adminer.org